Research On Stable Tracking Control For Quadrotor Unmanned Aerial Vehicle

The quadrotor UAV,which has small size,light mass and simple structure with strong security,flexibility and maneuverability,has significant value of military and civilian,such as the ground battlefield reconnaissance and surveillance in real time,the search and rescue after major natural disasters,environmental monitoring and aviation and so on.The quadrotor UAV with six degrees of freedom is a kind of coaxial rotor wing aircraft and has nonlinear characteristic,multivariable characteristic,strong coupling and uncertainty.It will be affected by a variety of physical effect and the external disturbance in actual flight and has been hotspot and difficulty in the flight control field.In order to realize the stable tracking control of the quadrotor UAV and improve the flight quality,its controller design research need to be carried out.Besides,the quadrotor UAV can be regarded as research platform to study nonlinear system control and intelligent control,which has very important research value.In this paper,the quadrotor UAV modeling is carried out based on Newton-Euler formula and Lagrangian-Euler formula respectively.Controllers are designed According to the linear model and nonlinear model of attitude.The main research work is showed as follows:(1)The quadrotor UAV characteristics and force conditions are analyzed.A nonlinear dynamic model of the system is established.(2)Simplify the model of the quadrotor and design attitude controllers based on LQR and backstepping control whose effectiveness is verified by simulation and experiment.(3)According to the nonlinear model of the quadrotor UAV,unmodeled dynamics and external disturbance in attitude model are regarded as the system total disturbance.Then the attitude controller is designed based on ADRC.The simulation and experiment results show that ADRC controller can realize decoupling for the attitude angle and has disturbance rejection ability.Convergence of ESO and closed-loop stability is analyzed by Lyapunov theory.(4)According to the nonlinear model of the quadrotor UAV,a robust control structure is presented to achieve stable tracking control of the quadrotor UAV.A nonlinear 2H / H? mixed control method is used in the inner loop of control structure in the presence of parameter uncertainty and external disturbance in the output channel in order to realize stable tracking control of attitude angle and attitude angle velocity.Taking Euler Angle as time-varying parameters,LADRC controller is used in the outer loop of control structure to achieve position control.The simulation results indicate that the controller can obtain good performance and strong robustness.